If you wish to ask websites to respect your privacy, you can use the “Tell websites not to sell or share my data” setting. This option is built on top of the Global Privacy Control (GPC). GPC is respected by increasing numbers of sites and enforced with legislation in some regions.

So is the difference that DNT was asking for no tracking at all while this GPC setting allows for tracking data to be created but not forwarded to third parties? That seems reasonable, not all “tracking” is malicious. Though I wonder why, if DNT isn’t respected, any other vaguely similar setting would be.